GWiki is an embeddable Wiki engine. It allows users to edit rich text fragments in an application you develop. It supports I18N files and mulitimedia content.

Gwiki can be extended with macros written in Java or Groovy. It has a powerful right and role system, which can be fed from external sources such as LDAP, and allows access to business entitiels from wiki pages. It comes with Wicket integration out-of-the-box. Wicket-HTML-Fragments can be held within GWiki, so these pages can be managed by the Wiki System, while Wicket handles the application logic.
A desktop version of GWiki can be installed within seconds.
GWiki can be deployed as a servlet on every servlet container. GWiki can use a filesystem, a Zip archive, or a database or Google Appengine DataStorage for its content storage.